If you're a healthcare company, going straight to employers might seem attractive because sales cycles can be shorter and they look for different things from their vendors that might be more product focused
but the hardest part of this channel is the number of "sales" you need to do. You need to go through:
1) the broker, who's helping the employer pick their benefits and frequently marketing on behalf of the vendors
2) The third-party administrator that you need to work with to make everything work correctly
3) the employer who needs to be convinced you're right for them and their employees (from a price perspective)
4) The employee themselves, who actually needs to enroll in your service for it to be useful
So the problem is now your product needs to be attractive to a whole host of different people (e.g. their are tradeoffs between making something useful to employees and financially attractive to employers)
AND usually every intermediary wants a pound of flesh this process happens for every employer, which means your customer acquisition costs skyrocket